Batboard

Okay, this may sound stupid, but I have to ask.. when our medic units key their radios (unsure what kind) you get a chirp/screech noise, similar to the Nextel noise. What is that? My fire department's radios do not do that (except for the few Ericsson portables we have). What purpose do these tones serve, and are there ways to change them? I'll take whatever additional information there is on this.. curiosity killed the cat..

Thanks...

--Chris

Well, a little more information would help. What make/model radio is it. What kind of radio system is it... conventional or trunked?

VHF high band, conventional. I'm not sure what kind of radio it is that they use. We're all on the same system (EMS and Fire) on 154.2500 mHz. We use M's stuff at my department, HT1000 portables, Maratrac mobiles in the apparatus, and none of them make the noise, except for some Ericsson's that we used to use. Hope this helps...?

If it's a long tone, prob. pre-mdc pttid.

-Alex

It may have something to do with the encoding to the hospital ER, we still have quite a few hospitals in our area that still use the H.E.A.R. system to open their radios.

I'm pretty sure the "chirp" you describe is (pre-ptt) mdc signaling with DOS enabled- The dos (data operated squelch) strips most of the audible data burst you hear with MDC- leaving you with a "chirp" sound.